Flexible Manufacturing System (FMS)

It is a configuration of :

A group of production machines or work stations (usually CNC) connected by automatic material handling & transferring m/cs

& integrated & controlled by a computer system which can give instructions to produce a large variety of products in any order specified.

Components of FMS: Processing Stations These are usually Computer Numerical Control (CNC) m/cs that perform machining operations on families of parts. They are designed with other types of equipments including Inspection stations, assembly work heads & sheet metal processing. Most of the machines in FMS utilize randomly selectable heads to perform functions such as drilling, tapping etc. (91 A / B & 576 MT)

Flexible Manufacturing System (FMS)-contd

• Material Handling Device

Various types of material handling equipments are used to transport to transport work parts & sub assemblies between processing stations. For work transportation individual conveyors are used. The load & unload stations are used for loading & unloading of raw material & finished parts.

• Auxiliary Equipments:

Apart from machine tools, FMS can also include cleaning, automated measurement & inspection equipments.

• Computer Control System:

Computer Control is used to co-ordinate the activities of the processing stations & material handling system. It oversees the operation of entire FMS.

Flexible Manufacturing System (FMS)-contd

• Some of the main functions of controller are:o Machine Control (CNC, DNC)o Production controlo Tools controlo Traffic & shuttle controlo Work handling system controlo Monitoring, controlling & reporting system performance.

Flexible Manufacturing System (FMS)-contd

• Flexible Manufacturing System

Tool Changer

Tool Changer

Tool Changer

CNC 1 CNC 2 CNC 3

Out In Out In Out In

AS / RS

Raw Material Storage ( Roller Conveyor)

L / U L / U

AGV 1

Temporary Storage areas

AGV 2

Raw Material storage(Floor Space)

Raw

mat

eria

l sto

rage

( F

loor

spa

ce)

Com

pute

r C

ontr

ol

Load / Unload Stations92 / A/B / Kackar

AGV – Automated Guided Vehicles

ASRS – Automated Storage & Retrieval System.

Flexible Manufacturing System (FMS)-contd

• These can be broadly grouped in to • Flexible transfer lines• Flexible Manufacturing cells• Stand alone NC machine.

The nos. & types of machines may differ.

FMS means a fully automated system consisting of :

Automated work station, Automated material handling &computer control

Applications of FMS characteristics:

FMS

Transfer line

Stand alone CNC

Low Medium High

Production Volume

High

Medium

Low

Fle

xibi

lity

&

Var

iety

of p

artsFMS are used for mid

Volume for mid volumeRange between high volume transfer lines &low volume stand aloneNC-CNC machines.

Flexible Manufacturing System (FMS)-contd• FMS work stations: Various types of machines used are

• Machining Centers: It is a highly automated stand alone m/c which can be used as a component of FMS. Special features like automated tool changing & tools storage, use of palletized work parts CNC control makes it more compatible with FMS.

• Head Changers: It is a special machine tool with capability to change tool heads. Tool heads are usually multiple spindle tools module s that can be stored in a rack or a drum located on or near the machine. They are used for multiple simultaneous operations.

• Head Indexers: IN this the heads are attached semi permanently to an indexing mechanism on the machine tool.

• Milling Modules: Special milling machine modules help to achieve higher production levels than machine centre. A milling module can be horizontal spindle, vertical spindle, or multi spindles.

• Turning Modules: Many of the parts made on FMS are held in a pallet fixture throughout processing on the FMS, thus turning modules must be designed to rotate the single point tool around the work.

(578 MT)

Flexible Manufacturing System (FMS)-contd• Assembly work stations: Industrial robots are usually considered

to be most appropriate for automated assembly work stations in FMS. Theu can be programmed to perform tasks with variation in sequence & motion patterns to accommodate the different products made on the system.

• Inspection Stations : Inspection can be included in FMS either at the workstations or by designing special inspection stations. Coordinate measuring machines , special inspection probes , that can be used in machine tool spindle & machine vision.

• Sheet metal processing machine : Includes processing machines for operations such as punching, shearing, bending, forming etc.

• Forging Stations: FMS are developed to automate the forging. (578 MT)

Flexible Manufacturing System (FMS)-contd• Designing FMS: Designing &developing FMS fall in 2- catagories:

1 Initial specification decision include:• Type of parts to be produced ( variety)• Process planning for these parts• Type of flexibility required• Type of FMS to be developed.• Type capacity, specification, of material handling systems.• Decide the control system i.e. hierarchy of computer control.• 2 Implementation decision:• Determination of layout of FMS• Determine the no. of pallets required.• Determine the type & no. of each type of fixture & design of these• fixture• Specification of strategies for FMS. (579 MT)

Flexible Manufacturing System (FMS)-contd• Advantages & Limitations of FMS

Advantages: - Greater flexibility

Provides manufacturing facilities which are flexibility for family of

work piece i.e. there will be greater potential to make changes in

terms of products, technology as needed.

- Reduction in direct labour

Reduces manual material handling, &

automation control of machines make it possible to operate an FMS

with less direct labour.

- Reduced Capital Investment

Machine utilization with FMS can be about 3-times as high as with

conventional machining . Hence fewer machines are required, less

toolings to equip them, hence less inventory, lower space & hence

less capital. (579 MT)

contd.

Flexible Manufacturing System (FMS)-contd - Shorter response time: As majority of the work is done automatically. The lead time for production is hence very low & the response time will be shorter.

- Consistent quality: Due to automation human error is minimized & hence consistent quality. - Better control of work

Limitations: i) Some kind of standardization of part design is required to reduce tooling. ii) FMS requires long planning & development cycle to ensure the success of the system. (579 MT/ kackar)